Exploration and Scarcity
指出资源租金作为稀缺性指标不可观测，但可通过可观测的边际勘探成本来推断，并用两期模型分析勘探不确定性对开采和勘探决策的影响，最后用美国油气勘探成本数据说明其变化趋势。
Noting that a suggested measure of natural resource scarcity, resource rent, is unobservable, we show that rent is linked to (observable) marginal exploration cost. A two-period model of extraction and exploration reveals that rent is equal to this cost when discovery is certain. Under risky exploration, cost data can be used to bound rent. The model also indicates how exploration uncertainty affects the competitive firm's extraction and exploration decisions. Finally, the behavior of U.S. oil and gas exploration costs suggests that these costs were rising in the postwar era, which has different implications for scarcity than indicated by other measures of scarcity.